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An initiation-promotion model of tumour prevalence from high-charge and energy radiationsA repair/misrepair kinetic model for multiple radiation-induced lesions (mutation inactivation) is coupled to a two-mutation model of initiation-promotion in tissue to provide a parametric description of tumour prevalence in the mouse Harderian gland from high-energy and charge radiations. Track-structure effects are considered using an action-cross section model. Dose-response curves are described for gamma rays and relativistic ions, and good agreement with experiment is found. The effects of nuclear fragmentation are also considered for high-energy proton and alpha-particle exposures. The model described provides a parametric description of age-dependent cancer induction for a wide range of radiation fields. Radiosensitivity parameters found in the model for an initiation mutation (sigma 0 = 7.6 x 10(-10) cm2 and D0 = 148.0 Gy) are somewhat different than previously observed for neoplastic transformation of C3H10T1/2 cell cultures (sigma 0 = 0.7 x 10(-10) cm2 and D0 = 117.0 Gy). We consider the two hypotheses that radiation acts solely as an initiator or as both initiator and promoter and make model calculations for fractionation exposures from gamma rays and relativistic Fe ions. For fractionated Fe exposures, an inverse-dose-rate effect is provided by a promotion hypothesis with an increase of 30% or more, dependent on the dose level and fractionation schedule, using a mutation rate for promotion similar to that of single-gene mutations.
Document ID
20040089214
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
Authors
Cucinotta, F. A.
(NASA Langley Research Center Hampton VA United States)
Wilson, J. W.
Date Acquired
August 21, 2013
Publication Date
November 1, 1994
Publication Information
Publication: Physics in medicine and biology
Volume: 39
Issue: 11
ISSN: 0031-9155
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Radiation Health

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